1. Field of the Invention
The present invention relates to a oil level indicating system for an internal combustion engine in which the indicator extends through a passage running from the top of the engine into the engine's oil pan, without any external, add-on tubing being required.
2. Disclosure Information
Oil level indicating systems for internal combustion engines have generally included an indicator embodied as a wire or thin, flexible blade which is allowed to pass into liquid within the engine's crankcase sump, so as to provide a direct reading for the level of oil within the engine. Such indicators have commonly used externally mounted tubes which sometimes extend through a sidewall of a cylinder block. Unfortunately, such tubes may become damaged during operation of the vehicle, or during storage and installation of an engine. Further, such tubes take space which is almost always at a premium in modern automotive vehicle engine compartments. Although certain engines have indicators mounted in a boring formed at a lower portion of the cylinder block, such as at an oil pan rail, this is not a satisfactory solution either, because it is difficult to reinsert the indicator once it has been removed. And, contamination is a problem because of the buildup of road grime on the lower part of the block, which may be dislodged by the vehicle operator when the indicator is being reinserted with the result that the contamination will be pushed into the crankcase by the incoming oil indicator.
FIGS. 5 and 6 show a prior art attempt to mount an oil indicator through a camshaft cover of an engine. The embodiment of FIGS. 5 and 6 suffers from two problems. First, tube 84, which is pressed into cover 82, may cause an external oil leak if the joint between the tube and the boss into which it is pressed is not accurately and robustly made up. Furthermore, tube 84 becomes loose during use of the engine, and could fall down into the engine causing a major engine failure. Furthermore, because tube 84 extends only into the space of the cylinder head valve springs, and, perhaps, a camshaft, oil is free to splash on the indicator when it is installed, which may give a false reading in the event that an uninitiated motorist fails to adequately clean the indicator before attempting to ascertain the level of oil within the engine.
The present oil level indicating system overcomes the problems shown with the prior art systems by providing presentation of the indicator at the topmost part of an engine with a passageway system that prevents inaccurate oil readings, while also avoiding issues with potential impairment of the engine's operation.